AK49BWL
GMT400 Forever!
Playing around with these led me to a very interesting discovery.
It is in fact possible to utilize a head with the Bass/Treb buttons with a 5-Band cassette deck (and 5-EQ CDM) and still be able to use all the bands. How?
On some of the heads' wire harness is an extra wire with a connector on the end that seemingly has no use.
Through tracing the CDM board, I found that it's connected directly to the pin beside it, which is the CDM/Head data supply line. In addition, on the 5-EQ heads, this wire is also connected to the white wire in that extra 2-wire connector that plugs into the back of the cassette deck. So, cue some experimentation.
I plugged my Bass/Treb head into my 5-EQ CDM, and plugged that extra wire into the 5-EQ cassette's pin 2 (also a white wire internally). Lo and behold, all 5 bands lit up on the cassette deck, and the Bass/Treb buttons actually controlled the EQ display too!
So I found that pretty cool of course, the middle three bands still have to be controlled from the EQ itself.
I also discovered that the yellow wire in the 2-wire connector is for the EQ display dimming. The button backlighting gets its signal from the actual cassette player's harness, but there's no wire in that harness for LED display dimming. There's a voltage regulator in the head that operates the LED display dimming when the park lights are turned on, and this voltage regulator also runs the EQ display in the cassette deck via the yellow wire. More interesting stuff.
The 5-EQ heads actually have the Bass/Treb buttons internally bussed to work, just no external buttons mounted. And it turns out the two different heads have the exact same circuit boards in them, so guess who now has a Bass/Treb head with the extra 2-wire EQ connector
Why? Cuz I can
It is in fact possible to utilize a head with the Bass/Treb buttons with a 5-Band cassette deck (and 5-EQ CDM) and still be able to use all the bands. How?
On some of the heads' wire harness is an extra wire with a connector on the end that seemingly has no use.
You must be registered for see images attach
Through tracing the CDM board, I found that it's connected directly to the pin beside it, which is the CDM/Head data supply line. In addition, on the 5-EQ heads, this wire is also connected to the white wire in that extra 2-wire connector that plugs into the back of the cassette deck. So, cue some experimentation.
You must be registered for see images attach
I plugged my Bass/Treb head into my 5-EQ CDM, and plugged that extra wire into the 5-EQ cassette's pin 2 (also a white wire internally). Lo and behold, all 5 bands lit up on the cassette deck, and the Bass/Treb buttons actually controlled the EQ display too!
You must be registered for see images attach
So I found that pretty cool of course, the middle three bands still have to be controlled from the EQ itself.
I also discovered that the yellow wire in the 2-wire connector is for the EQ display dimming. The button backlighting gets its signal from the actual cassette player's harness, but there's no wire in that harness for LED display dimming. There's a voltage regulator in the head that operates the LED display dimming when the park lights are turned on, and this voltage regulator also runs the EQ display in the cassette deck via the yellow wire. More interesting stuff.
The 5-EQ heads actually have the Bass/Treb buttons internally bussed to work, just no external buttons mounted. And it turns out the two different heads have the exact same circuit boards in them, so guess who now has a Bass/Treb head with the extra 2-wire EQ connector
You must be registered for see images attach
Why? Cuz I can
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